What is the water table?

What is the water table?

• A. Surface of the earth
• B. Top of groundwater; above the water table is dry, below the water table is saturated
• C. The boundary between the crust and mantle
• D. The bottom of the ocean

Answer: (B)

The water table is the dividing surface between the unsaturated zone above and the saturated zone below in the subsurface. In the soil above this level, air and water occupy pore spaces; below it, all the spaces are filled with water. So, it’s the upper boundary of groundwater—the top of the groundwater zone. This isn’t the Earth’s surface itself, nor the boundary between the crust and mantle, nor the bottom of the ocean. Its position can rise or fall with rainfall, recharge, and withdrawal, and wells tap water from the saturated zone just below it.

The water table is the dividing surface between the unsaturated zone above and the saturated zone below in the subsurface. In the soil above this level, air and water occupy pore spaces; below it, all the spaces are filled with water. So, it’s the upper boundary of groundwater—the top of the groundwater zone. This isn’t the Earth’s surface itself, nor the boundary between the crust and mantle, nor the bottom of the ocean. Its position can rise or fall with rainfall, recharge, and withdrawal, and wells tap water from the saturated zone just below it.